Suddenly as his introspective gaze wandered unconsciously over the ground before him, his attention was arrested by a second mark of the same perplexing shape, which he could see behind a rose-bush, more than half-way across the bed. Stepping as near the hedge as he could, the detective proceeded to examine this duplicate of the riddle. It seemed absolutely the same, though deeper, as was natural on the soft mould, and he found, by measuring, that it lay exactly parallel to the other. What could it be, he asked himself. A moment later, still another and yet stranger impression caught his eye. It was about the same width, but not more than half as long, and rounded off at each end to an oval. It was situated about a foot from the deep indentation and rather farther from the holly hedge. A tall standard rose-tree, covered with blossoms of the white Frau Karl Drouski rose, grew near it, interposing between it and the house.
Gimblet measured it with painstaking precision; then with the help of his measurements, he made a life-size diagram of it on the page of his notebook, and studied it with an expression of annoyance. He had seldom felt more at a loss to explain anything. At length he turned and went back towards the grass.
"What a track I leave," he thought to himself, looking down ruefully at his own footprints. "What I want is--" He stopped abruptly as a sudden idea struck him; then a look of relief stole slowly over his face, and he permitted himself a gratified smile, "To be sure!" he said, and seemed to dismiss the subject from his mind.
Indeed, he turned his back upon the rose-bed, and strolled away by the side of the hedge, which was of tall and wide proportions, providing a spiky, impenetrable defence against observation, from the outside, of the rectangular enclosed garden. Half-way along it he came upon an arched opening. Passing through this, he found himself in an outer thicket, and immediately upon his right hand beheld a small shed, which stood back, modest and unassuming, in a leafy undergrowth of rhododendrons.
Gimblet pushed open the door and stepped inside.
The place was evidently a tool-house, used by the gardeners for storing their implements. Rakes, spades, forks and hoes leant against the walls; a shelf held a quantity of odds and ends: trowels, seedsmen's catalogues, a pot of paint, a bundle of wooden labels, the rose of a watering-can, and a dozen other small objects. On the floor were piled boxes and empty cases; flowerpots stood beside a bag which bore the name of a patent fertilizer; a small hand mowing-machine blocked the entrance; and a plank, too long to lie flat on the ground, had been propped slantwise between the floor and the roof. Bunches of bass hung from nails above the shelf; and on the wall opposite, a coloured advertisement, representing phloxes of so fierce an intensity of hue that nature was put to the blush, had been tacked by some admirer of Art.
